document.write( "Question 43222This question is from textbook algebra and trigonometry with analytic geometry
\n" ); document.write( ": find the point on the positive y-axis that is a distance 5 from the point P(3,4). I plotted it out to be B(0,8) But I'm not sure if this is right. Thanks for looking it over. \n" ); document.write( "
Algebra.Com's Answer #28247 by psbhowmick(878)\"\" \"About 
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CONSTRUCTIONAL METHOD:\r
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\n" ); document.write( "\n" ); document.write( "First locate the point P(3,4) on a graph paper.
\n" ); document.write( "Then draw a circle with centre at (3,4) and radius equal to 5 units.
\n" ); document.write( "This circle intersects the y-axis at two points A and B.
\n" ); document.write( "Find out the coordinates of these points from the graph.
\n" ); document.write( "You shall find coordinates of A and B are (0,8) and (0,0) respectively.\r
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\n" ); document.write( "\n" ); document.write( "Both points A and B lies on y-axis and are at a distance of 5 units from P but only A lies on the positive y-axis. So the required point is A and the coordinates are (0,8).\r
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\n" ); document.write( "\n" ); document.write( "ALTERNATIVE METHOD:\r
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\n" ); document.write( "\n" ); document.write( "The distance 'd' between two points (\"x%5B1%5D\",\"y%5B1%5D\") and (\"x%5B2%5D\",\"y%5B2%5D\") is given
\n" ); document.write( "\"d+=+sqrt%28%28x%5B1%5D-x%5B2%5D%29%5E2+%2B+%28y%5B1%5D-y%5B2%5D%29%5E2%29\" ____________(1)\r
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\n" ); document.write( "\n" ); document.write( "In this problem let the coordinates of A and B are (\"x%5B1%5D\",\"y%5B1%5D\") and (\"x%5B2%5D\",\"y%5B2%5D\") respectively.
\n" ); document.write( "Here, \"d\" = 5, \"x%5B1%5D\" = 3, \"y%5B1%5D\" = 4, \"x%5B2%5D\" = 0 and \"y%5B2%5D\" = ?
\n" ); document.write( "[Note \"x%5B2%5D+=+0\" because the point (\"x%5B2%5D\",\"y%5B2%5D\") has to lie on y-axis]
\n" ); document.write( "Putting these values in (1) we have
\n" ); document.write( "\"5+=+sqrt%28%283-0%29%5E2+%2B+%284-y%5B2%5D%29%5E2%29\"
\n" ); document.write( "Squaring both sides
\n" ); document.write( "\"5%5E2+=+3%5E2+%2B+%284-y%5B2%5D%29%5E2\"
\n" ); document.write( "or \"5%5E2+-+3%5E2+=+%284-y%5B2%5D%29%5E2\"
\n" ); document.write( "or \"25+-+9+=+%284-y%5B2%5D%29%5E2\"
\n" ); document.write( "or \"16+=+%284-y%5B2%5D%29%5E2\"
\n" ); document.write( "or \"4%5E2+-+%284-y%5B2%5D%29%5E2+=+0\"
\n" ); document.write( "or \"%284+%2B+%284-y%5B2%5D%29%29%284+-+%284-y%5B2%5D%29%29+=+0\"
\n" ); document.write( "or \"%288-y%5B2%5D%29y%5B2%5D%29+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "Hence either \"8+-+y%5B2%5D\" = 0 i.e. \"y%5B2%5D\" = 8 or \"y%5B2%5D\" = 0.
\n" ); document.write( "As the reqd. point must be on positive y-axis, so \"y%5B2%5D+=+8\" is the only possibility.\r
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\n" ); document.write( "\n" ); document.write( "Thus the coordinates of the point A which lie on positive y-axis and is at a distance of 5 units from (3,4) are (0,8).
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